Conventional decorative water or waterfall displays are typically constructed for indoor or outdoor use in pools, spas or the like. These water or waterfall displays generally use a plurality of water chambers and wide, flat spouts to create thick and discontinuous streams of water that fall a short distance into the pool or spa below. One of the problems with such devices is that they are primarily designed for use with large volumes of water, which makes it difficult to use the devices in indoor water displays. Moreover, such prior art waterfall displays do not form a continuous film or layer of downwardly flowing water, but rather form thick, turbulent streams which tend to splash and are not particularly attractive as a decorative display. Additionally, the waterfall produced by such devices tends to separate into one or more generally cylindrical streams of water as it falls because of the strong surface tension of water that tends to pull the water flow together. Examples of such devices are disclosed in U.S. Pat. Nos. 4,881,280 to Lesikar; 5,537,696 to Chartier; and 5,738,280 to Ruthenberg.
Decorative indoor water displays are known in the art. However, the known indoor water displays do not create an unsupported film or laminar sheet of water. Instead, such displays are characterized by flowing water over a solid or broken solid surface, such as an inclined or vertical plate. The water adheres to the plate surface as it cascades down. Such displays do not create a transparent film of water, but merely flow water over an existing structure to create a rippling effect. An example of such a device is disclosed in U.S. Pat. No. 4,747,583 to Dunn et al.
Indoor displays that are used to advertise oil are known in the art. One of the problems associated with the existing advertising display devices is that in order to function, they require the use of viscous fluids, such as lubricating oil. U.S. Pat. No. 1,689,790 to Lefevre, Jr. discloses an oil display device. Lefevre, Jr. however, is limited to maintaining a thin film of viscous liquid. The device relies on the high viscosity of the liquid displayed to create a film. Another problem associated with the Lefevre, Jr. device is that in order to maintain contact between the viscous liquid and two guides, it relies on forming the guides such that they converge at the bottom of the device. As a result of these deficiencies, the device disclosed would not be able to maintain a film of aqueous liquid. Similarly, U.S. Pat. No. 1,837,225 to Lipski discloses an oil display device for displaying cyclic movement of an oil film, and is adapted for use only with lubricating oils and other liquids with high molecular adhesion. The Lipski device is similarly not suited for low viscosity liquids, such as water or aqueous liquids which have low molecular adhesion and high molecular cohesion.
The devices disclosed in the aforementioned patents suffer from many deficiencies as described above. It would be desirable, therefore, to provide a decorative and educational indoor waterfall which utilizes a low viscosity liquid, such as water or other aqueous liquid, to form an attractive display of a continuous liquid film between two limiting guides. From the standpoint of education, it would be desirable to provide a waterfall device that is not only decorative, but also is suitable for use as a demonstrative aid in teaching the physics of liquid flow, surface tension and other hydrodynamic concepts.